From the state of the art, it is known—especially relating to drawing frames—that the fiber material drafted by the drafting system, which is mostly available as fiber fleece after the drafting system, is guided through a compressor (shaped like a fleece funnel, for example) and afterwards transported towards a spinning can with the help of one or several rotatable draw-off elements such as a pair of draw-off disks, for example. Here, an additional draft (a so-called tension draft) can be generated between the drafting system and the draw-off elements by selecting a higher circumferential speed of the draw-off elements than the circumferential speed of the drafting system's exit cylinder placed upstream from the compressor in transportation direction.
It is likewise known that the fiber sections of the fiber fleece drafted with the help of the drafting system enter the compressor along parallel running paths during the normal operation of the drafting system (i.e. between the corresponding starting and stopping phases, in which the circumferential speed of the exit cylinder—and with it, the feeding speed of the drafting system—turns out to be lower than during normal operation. In the compressor, they finally strike its rebounding surface, are then deflected here more or less abruptly and finally leave the compressor through a passage opening so the draw-off disks can transport them away towards the spinning can.
Although the change of direction inside the compressor mentioned above is certainly desired and leads to higher tensile strength or tear resistance (the textile engineer calls this an increase in so-called “sliver adhesion”) through the corresponding swirling actions inside the compressor. As the fiber fleece moves slower during the starting and stopping phase, the flow pattern described here, however, cannot be maintained in these phases of operation of the drafting system. Rather, the individual fiber strand sections inside the compressor acquire, as a rule, a funnel-shaped flow pattern—in other words, the fiber band sections enter the compressor in parallel and with almost the same speeds (other than during the normal operation of the drafting system), so that the swirling action mentioned above does not take place and sliver adhesion turns out to be lower than during normal operation.